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| United States Patent |
6,135,345
|
|
Shimizu
, et al.
|
October 24, 2000
|
Metal material bonding method
Abstract
In a metal material bonding method, an insertion material, which has a
lower melting point than that of metal materials to be bonded, is
interposed between bonding end surfaces of the metal materials to be
bonded. The metal materials to be bonded is heated and held to a
temperature not lower than the melting point of the insertion material and
not higher than the melting point of the metal materials to be bonded
while applying pressure to bonding surfaces of the metal materials to be
bonded. The insertion material is formed to have a size which is smaller
than each of the bonding surfaces of the metal materials to be bonded.
| Inventors:
|
Shimizu; Takao (Nagoya, JP);
Yamamoto; Noboru (Nagoya, JP);
Inagaki; Shigeyuki (Nagoya, JP);
Suzuki; Hiroaki (Nagoya, JP)
|
| Assignee:
|
Daido Tokushuko Kabushiki Kaisha (JP)
|
| Appl. No.:
|
246709 |
| Filed:
|
February 9, 1999 |
Foreign Application Priority Data
| Feb 10, 1998[JP] | 10-044452 |
| Current U.S. Class: |
228/245; 228/246; 228/249 |
| Intern'l Class: |
B23K 035/12 |
| Field of Search: |
228/245,246,249,262.1,262.3,262.4
|
References Cited
U.S. Patent Documents
| 3668359 | Jun., 1972 | Emmerson | 219/60.
|
| 4153194 | May., 1979 | Leonard, Jr. | 228/29.
|
| 5316202 | May., 1994 | Murray et al. | 228/5.
|
| 5660317 | Aug., 1997 | Singer et al. | 228/44.
|
| 5699995 | Dec., 1997 | Shimizu et al. | 228/194.
|
| 5831252 | Nov., 1998 | Shimizu | 219/603.
|
| Foreign Patent Documents |
| 0 278 030 | Aug., 1988 | EP.
| |
| 63-140781 | Jun., 1988 | JP.
| |
| 402015196 | Jan., 1990 | JP | 228/1.
|
| 363120608 | Aug., 1994 | JP | 228/1.
|
| 406226468 | Aug., 1994 | JP | 228/3.
|
| 07120996 | Nov., 1996 | JP.
| |
Primary Examiner: Mills; Gregory
Assistant Examiner: Pittman; Zidia T.
Attorney, Agent or Firm: Bacon & Thomas PLLC
Claims
What is claimed is:
1. A metal material bonding method comprising the steps of:
interposing an insertion material, which has a lower melting point than
that of metal materials to be bonded, between bonding end surfaces of the
metal materials to be bonded; and
heating and holding the metal materials to be bonded to a temperature not
lower than a melting point of the insertion material and not higher than a
melting point of the metal materials to be bonded while applying pressure
to bonding surfaces of the metal materials to be bonded;
wherein the insertion material has a size which is smaller than each of the
bonding surfaces of the metal materials to be bonded such that there is a
distance between an outer edge of the insertion material and an outer edge
of the metal materials to be bonded.
2. A metal material bonding method according to claim 1, wherein each of
the metal materials to be bonded is a solid material;
the insertion material is formed of an Ni-group or Fe-group alloy
containing boron in a range of from 2.0 mass % to 5.0 mass % and has a
thickness in a range of from 20 .mu.m to 100 .mu.m;
a ratio of the area of the insertion material to the area of each of the
bonding surfaces of the metal materials to be bonded is in a range of from
50% to 99%; and
the distance between the outer edge of the insertion material and the outer
edge of each of the metal materials to be bonded is not smaller than a
value ten times as large as the thickness of the insertion material.
3. A metal material bonding method according to claim 1, wherein each of
the metal materials to be bonded is a hollow material;
the insertion material is formed of an Ni-group or Fe-group alloy
containing boron in a range of from 2.0 mass % to 5.0 mass % and has a
thickness in a range of from 20 .mu.m to 100 .mu.m;
a ratio of the area of the insertion material to the area of each of the
bonding surfaces of the metal materials to be bonded is in a range of from
50% to 99%;
the distance between the outer edge of the insertion material and the outer
edge of each of the metal materials to be bonded is not smaller than a
value ten times as large as the thickness of the insertion material; and
a distance between an inner edge of the insertion material and an inner
edge of each of the metal materials to be bonded is not larger than a
value one hundred times as large as the thickness of the insertion
material.
4. A metal material bonding method according to claim 1, wherein the
surface roughness R.sub.max of each of the bonding surfaces of the metal
materials to be bonded is not larger than 50 .mu.m;
the pressure applied to the bonding surfaces of the metal materials to be
bonded is in a range of from 3 MPa to 9 Mpa; and
the heating and holding is performed in a non-oxidative atmosphere.
5. A metal material bonding method according to claim 4, wherein the
heating and holding is performed in an atmosphere of inert gas.
6. A metal material bonding method according to claim 5, wherein the inert
gas is selected from an Ar gas, an N.sub.2 gas and a mixture gas of Ar and
N.sub.2.
7. A metal material bonding method according to claim 4, wherein the
heating and holding is performed in a substantial vacuum.
8. A metal material bonding method according to claim 7, wherein the
substantial vacuum has a pressure not higher than 5.times.10.sup.-2 mmHg.
9. A metal material bonding method according to claim 1, wherein the
heating is performed by induction heating or high frequency resistance
heating.
10. A metal material bonding method according to claim 9, wherein the
frequency of a current in the induction heating or resistance heating is
in a range of from 3 kHz to 100 kHz.
11. A metal material bonding method according to claim 2, wherein the
insertion material is formed of an Ni-group or Fe-group alloy containing
boron in a range of from 3.0 mass % to 4.0 mass %.
12. A metal material bonding method according to claim 3, wherein the
insertion material is formed of an Ni-group or Fe-group alloy containing
boron in a range of from 3.0 mass % to 4.0 mass %.
13. A metal material bonding method according to claim 10, wherein the
frequency of the current in the induction heating or resistance heating is
in a range of from 3 kHz to 30 kHz.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a metal material bonding method. More
specifically, it relates to improvement in a metal material bonding method
in which an insertion material is interposed between the metal materials
to be bonded.
2. Description of the Related Art
Heretofore, a bonding method using an insertion material interposed between
materials to be bonded to each other has been employed in liquid-phase
diffusion bonding.
However, because the insertion material used is formed to have a shape and
a size so as to cover the whole of bonding surfaces, there arises a
problem that the insertion material is partially extruded between
materials to be bonded at the time of bonding so that surfaces of the
bonding portions of the materials to be bonded are covered with the
insertion material. When the bonding portions are under such a condition,
the insertion material extruded and solidified so as to cover the surfaces
of the bonding portions of the materials to be bonded exerts a notching
effect so that strength against fatigue of bonding is lowered. Therefore,
the work of removing the insertion material covering the surfaces of the
bonding portions of the materials to be bonded after bonding is required.
There arises also a problem that this brings about lowering of
productivity or workability.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a metal material
bonding method in which an insertion material interposed between bonding
surfaces of the materials to be bonded is prevented from excessively
covering bonding end portions of the materials to be bonded at the time of
bonding.
According to the present invention, the metal material bonding method
comprises the steps of: interposing an insertion material, which has a
lower melting point than that of metal materials to be bonded, between
bonding end surfaces of the metal materials to be bonded; and heating and
holding the metal materials to be bonded to a temperature not lower than
the melting point of the insertion material and not higher than the
melting point of the metal materials to be bonded while applying pressure
to bonding surfaces of the metal materials to be bonded, wherein the
insertion material is formed to have a size which is smaller than each of
the bonding surfaces of the metal materials to be bonded.
According to a first embodiment of the metal material bonding method of the
present invention, each of the metal materials to be bonded is provided as
a solid material; the insertion material is formed of an Ni-group or
Fe-group alloy containing boron in a range of from 2.0 mass % to 5.0 mass
% (preferably, 3.0 mass % to 4.0 mass %) and has a thickness in a range of
from 20 .mu.m to 100 .mu.m (preferably, 30 .mu.m to 50 .mu.m); the ratio
of the area of the insertion material to the area of each of the bonding
surfaces of the metal materials to be bonded is in a range of from 50% to
99% (preferably, 70% to 85%); and the distance between the outer edge of
the insertion material and the outer edge of each of the metal materials
to be bonded is not smaller than a value ten times (preferably, fifteen
times) as large as the thickness of the insertion material.
According to a second embodiment of the metal material bonding method of
the present invention, each of the metal materials to be bonded is
provided as a hollow material; the insertion material is formed of an
Ni-group or Fe-group alloy containing boron in a range of from 2.0 mass %
to 5.0 mass % (preferably, 3.0 mass % to 4.0 mass %) and has a thickness
in a range of from 20 .mu.m to 100 .mu.m (preferably, 30 .mu.m to 50
.mu.m); the ratio of the area of the insertion material to the area of
each of the bonding surfaces of the metal materials to be bonded is in a
range of from 50% to 99% (70% to 85%); the distance between the outer edge
of the insertion material and the outer edge of each of the metal
materials to be bonded is not smaller than a value ten times as large as
the thickness of the insertion material; and the distance between the
inner edge of the insertion material and the inner edge of each of the
metal materials to be bonded is not larger than a value one hundred times
as large as the thickness of the insertion material (preferably, the inner
edge of each of the metal materials to be bonded is not smaller than a
value ten times as large as the thickness of the insertion material).
In the metal material bonding method of the present invention, it is
preferable that the surface roughness R.sub.max of each of the bonding
surfaces of the metal materials to be bonded is not larger than 50 .mu.m;
the pressure applied to the bonding surfaces of the metal materials to be
bonded is in a range of from 3 MPa to 9 MPa; and the heating and holding
is performed in a non-oxidative atmosphere.
In the metal material bonding method of the present invention, it is
preferable that the heating is performed by means of induction heating or
high frequency resitance heating.
In this case, it is preferable that the frequency of a current in the
induction heating or resistance heating is in a range of from 3 kHz to 100
kHz (preferably, 3 kHz to 30 kHz).
In the metal material bonding method according to the present invention,
the size of the insertion material is adjusted so that the insertion
material is set inward by a predetermined quantity from the outer edge of
each of the bonding surfaces of the metal materials to which the insertion
material is bonded. Accordingly, a part of the insertion material is
prevented from being excessively extruded to the bonding end portions at
the time of bonding. Accordingly, the strength against the fatigue of the
bonding portions is prevented from being lowered by the insertion material
which is extruded to the surfaces of the bonding portions and solidified
thereat.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIG. 1 is a schematic view of a bonding apparatus used in Embodiment 1 of
the present invention;
FIG. 2 is a view showing a state in which an insertion material used in
this Embodiment 1 is attached to bonding surfaces of the metal materials
to be bonded to each other;
FIG. 3 is a view showing a state in which an insertion material used in
Embodiment 2 of the present invention is attached to bonding surfaces of
the metal materials to be bonded to each other;
FIG. 4 is a schematic view of a bonding apparatus used in Embodiment 3 of
the present invention;
FIG. 5 is a schematic view of a bonding apparatus used in Embodiment 5 of
the present invention; and
FIG. 6 is a schematic view of a bonding apparatus used in Embodiment 7 of
the present invention.
PREFERRED EMBODIMENTS OF THE INVENTION
Preferred embodiments of the present invention will be described below with
reference to the accompanying drawings but the present invention is not
limited to those embodiments.
Embodiment 1
FIG. 1 is a schematic view showing a main part of a bonding apparatus used
in Embodiment 1 of the metal material bonding method according to the
present invention. In this bonding apparatus A, metal round rods
(hereinafter merely called "round rods") are used as metal materials 1 and
2 to be bonded to each other. An insertion material 3 is interposed
between bonding surfaces of the round rods 1 and 2. An inert gas, such as
an Ar gas, an N.sub.2 gas, a mixture gas of Ar and N.sub.2, or the like,
is supplied from an inert gas supply source 5 into a housing 6 which
receives the round rods 1 and 2 to be bonded to each other, so that the
inside of the housing 6 is set in an atmosphere of inert gas. While
bonding portions of the round rods 1 and 2 are pressed by a pressing
device 4 and while bonding end portions of the round rods 1 and 2 are
heated by an induction heating device 7 in the atmosphere of inert gas,
the round rods 1 and 2 are diffusion-bonded to each other. If bonding is
performed in an oxidative atmosphere, oxygen grasped between the end
surfaces of the metal materials reacts with the insertion material to form
oxide. If the oxide remains in the bonding surfaces, mechanical
characteristic of the bonding is lowered. Accordingly, bonding is
preferably performed in a non-oxidative atmosphere such as an inert gas
atmosphere, or the like. Incidentally, in FIG. 1, the reference numeral 8
designates a high-frequency electric source device for the induction
heating device. Further, in FIG. 1, the thickness of the insertion
material 3 is exaggerated for convenience of description.
The insertion material 3 is provided as a disk formed of an Ni-group or
Fe-group alloy containing boron in a range of from 2.0 mass % to 5.0 mass
%. The thickness of the insertion material 3 is in a range of from 20
.mu.m to 100 .mu.m. Boron not only has an effect of decreasing the melting
point of the Ni-group alloy but also has a high diffusion speed so as to
be diffused from the dissolved insertion material 3 into a solid base
material easily. An "isothermal solidification phenomenon" is generated in
such a manner that the boron content of the dissolved insertion material 3
is reduced because of the diffusion of boron from the dissolved insertion
material 3 into the solid base material, so that the melting point of the
dissolved insertion material 3 rises. As a result of the "isothermal
solidification phenomenon", the materials to be bonded to each other are
fused firmly. However, if the boron content in the insertion material 3 is
smaller than 2 mass %, the effect is insufficient. If the boron content is
contrariwise larger than 5 mass %, the melting point of the insertion
material 3 rises to simply increase the time required for diffusing boron
from the dissolved insertion material 3 into the solid base material.
Accordingly, in this Embodiment 1, the upper limit is set to 5 mass %. In
this case, the boron content in the insertion material 3 is more
preferably in a range of from 3 mass % to 4 mass %.
If the thickness of the insertion material 3 is less than 20 .mu.m, not
only it is impossible to obtain an insertion material 3 dissolved enough
to make the roughness of the bonding surfaces even but also the
concentration distribution of various components in the insertion material
3 becomes uneven so that it is impossible to produce any foil-like sheet
in an extreme case. If the thickness of the insertion material 3 is more
than 100 .mu.m, the melted insertion material 3 is excessively extruded to
the surfaces of the bonding portions by lo the "pressing force" applied to
the bonding surfaces so that not only the quality of external appearance
is spoiled but also the protruded portions of the insertion material 3
extruded to the surfaces of the bonding portions and solidified thereat
become concentrated stress sources to deteriorate the mechanical
properties of the bonding in the case where the bonding portions are used
without being mechanically processed. Furthermore, the time required for
diffusing boron from the melted insertion material 3 into the solid base
material increases. Accordingly, the upper limit is set to 100 .mu.m. In
this Embodiment 1, the diameter of the insertion material 3 is slightly
smaller than that of each of the round rods, as shown in FIG. 2.
Specifically, the distance L.sub.0 from the outer edge of the insertion
material 3 to the outer edge of each of the round rods 1 and 2 is not
smaller than a value ten times as large as the thickness of the insertion
material 3. The ratio of the area of the insertion material 3 to the area
of each of the bonding surfaces of the round rods 1 and 2 is in a range of
from 50% to 99%. Here, the insertion material 3 formed of an Fe-group
alloy is preferably used in the case of bonding the round rods 1 and 2 of
carbon steel whereas the insertion material 3 formed of an Ni-group alloy
is preferably used in the case of bonding the round rods 1 and 2 of
stainless steel. Incidentally, the insertion material 3 is not necessary
to be always shaped like a disk if the aforementioned condition is
satisfied. For example, the insertion material 3 may be shaped like a
ring. Further, in FIG. 2, the distance Lo between the outer edge of the
insertion material 3 and the outer edge of the carbon steel round rod 1
(2) is exaggerated for convenience of description.
In a state in which the insertion material 3 is interposed between the
bonding surfaces of the round rods 1 and 2 to be bonded to each other, the
bonding surfaces are pressed by the pressing device 4. Here, the pressure
applied to the round rods 1 and 2 is in a range of from 3 MPa to 9 MPa. If
the pressure applied between the end surfaces of the metal materials, that
is, the pressure applied between the round rods 1 and 2 is lower than 3
MPa, the dissolved insertion material 3 cannot make the roughness of the
bonding surfaces even so that the mechanical properties of the bonding
deteriorate. On the contrary, if the pressure applied between the end
surfaces of the metal materials, that is, the pressure applied between the
round rods 1 and 2 is higher than 9 MPa, the bonding portions are deformed
excessively so that not only the quality of the external appearance is
spoiled but also the mechanical properties of the bonding is lowered.
Accordingly, the upper limit is set to 9 MPa. Further, to obtain uniform
bonding, the surface roughness R.sub.max of each of the end surfaces of
the round rods 1 and 2 to be bonded to each other is not larger than 50
.mu.m. If the surface roughness R.sub.max of each of the bonding surfaces
is larger than 50 .mu.m, the dissolved insertion material 3 cannot make
the roughness of the bonding surfaces even so that the mechanical
properties of the bonding deteriorate. Accordingly, the upper limit of
R.sub.max is set to 50 .mu.m.
Though not shown clearly, the induction heating device 7 has a heating
portion constituted by a ring coil. The frequency of a current flowing in
the ring coil should not be higher than 100 kHz. In either a
high-frequency induction heating method or a high-frequency resistance
heating method, only the surfaces are heated locally by the "skin effect"
as the frequency becomes high. Accordingly, if the temperature outside the
bonding surfaces reaches a predetermined value, the temperature of the
center portion (solid material) or the inside (pipe material) of the
bonding surfaces becomes excessively lower than the outside temperature,
and sufficient bonding strength cannot be obtained. Accordingly, the upper
limit of the frequency is set to 100 kHz. More preferably, the frequency
is in a range of from 3 kHz to 30 kHz. Incidentally, the heating portion
of the induction heating device 7 and the housing 6 covering the heating
portion are designed so as to be able to be halved. This is preferable
from the point of view of facilitating the setting and separation of the
round rods 1 and 2.
As described above, in this Embodiment 1, the disk-like or ring-like
insertion material 3 having a diameter slightly smaller than that of the
round rods 1 and 2 is used to perform diffusion bonding. Accordingly,
after bonding, the insertion material 3 is never excessively extruded to
the surfaces of the bonding portions. Accordingly, no finishing is
required on the bonding end portions after diffusion bonding. Accordingly,
the productivity and workability in diffusion bonding are improved
greatly.
Embodiment 2
In Embodiment 2 of the metal material bonding method according to the
present invention, metal round pipes (hereinafter merely called "round
pipes") 1 and 2 are used as the materials 1 and 2 to be bonded to each
other. An insertion material 3 is used so that the round pipes 1 and 2 are
bonded to each other by a bonding apparatus A shown in FIG. 1.
The insertion material 3 is provided as a ring of an Ni-group or Fe-group
alloy containing boron in a range of from 2.0 mass % to 5.0 mass %. The
thickness of the insertion material 3 is in a range of from 20 .mu.m to
100 .mu.m. In this Embodiment 2, the outer diameter of the insertion
material 3 is slightly smaller than that of each of the round pipes 1 and
2, as shown in FIG. 3. Incidentally, the insertion material 3 is hatched
for convenience of description. Specifically, the distance L.sub.0 from
the outer edge of the insertion material 3 to the outer edge of each of
the round pipes 1 and 2 is not smaller than a value ten times as large as
the thickness of the insertion material 3 whereas the distance L.sub.1
from the inner edge of the insertion material 3 to the inner edge of each
of the round pipes 1 and 2 is not larger than a value one hundred times as
large as the thickness of the insertion material 3. Further, the ratio of
the area of the insertion material 3 to the area of each of the bonding
surfaces of the round pipes 1 and 2 is in a range of from 50% to 99%.
Incidentally, with respect to other structures and operation/effect, the
Embodiment 2 is designed to be the same as the Embodiment 1. Further, in
FIG. 3, the distance L.sub.0 between the outer edge of the insertion
material 3 and the outer edge of the carbon steel round pipe 1 and the
distance L.sub.1 between the inner edge of the insertion material 3 and
the inner edge of the carbon steel round pipe 1 are exaggerated for
convenience of description.
Embodiment 3
FIG. 4 is a schematic view showing a main part of a bonding apparatus used
in Embodiment 3 of the metal material bonding method according to the
present invention. In this bonding apparatus A, an insertion material 3 is
interposed between bonding surfaces of round rods 1 and 2. Air in a
housing 6 which receives the round rods 1 and 2 to be bonded to each other
is discharged by a vacuum pump 11 so that the inside of the housing 6 is
evacuated to a near vacuum in which the pressure of the inside of the
housing 6 is not higher than 5.times.10.sup.-2 mmHg. While the bonding
portions are pressed by a pressing device 4 and while the bonding end
portions are heated in the near vacuum by an induction heating device 7,
the round rods 1 and 2 are diffused-bonded to each other. Incidentally, in
FIG. 4, the constituent parts corresponding to those in FIG. 1 are
referenced correspondingly.
With respect to the size, quality, etc., the insertion material 3 in this
Embodiment 3 is made the same as the insertion material 3 in the
Embodiment 1. Further, also the surface roughness of each of the bonding
surfaces of the round rods 1 and 2 which is pressed by the pressing device
4 in a state in which the insertion material 3 is interposed between the
bonding surfaces of the round rods 1 and 2, and the pressure and the
frequency of a current for pressing the round rods 1 and 2 are made to be
the same as those in the Embodiment 1, that is, the surface roughness is
not larger than R.sub.max =50 .mu.m; the pressure, in a range of from 3
MPa to 9 MPa; and the frequency of a current, not higher than 100 kHz.
Incidentally, the insertion material 3 may be shaped like a ring in the
same manner as in the Embodiment 1.
As described above, in this Embodiment 3, the disk-like or ring-like
insertion material 3 having a diameter slightly smaller than that of the
round rods is used to perform diffusion bonding. Accordingly, similarly to
the Embodiment 1, the insertion material 3 is never excessively extruded
to the surfaces of the bonding portions after bonding. Accordingly, no
finishing is required on the bonding end portions after diffusion bonding.
Accordingly, the productivity and workability in diffusion bonding are
improved greatly.
Embodiment 4
In Embodiment 4 of the metal material bonding method according to the
present invention, round pipes 1 and 2 are bonded to each other by a
bonding apparatus A shown in FIG. 4 with use of an insertion material 3.
The size and shape of the insertion material 3 in this Embodiment 4 are
made to be the same as those of the insertion material 3 in the Embodiment
2.
Incidentally, with respect to other structures and operation/effect, the
Embodiment 4 is made the same as the Embodiment 3.
Embodiment 5
FIG. 5 is a schematic view showing a main part of a bonding apparatus used
in Embodiment 5 of the metal material bonding method according to the
present invention. In this bonding apparatus A, an insertion material 3 is
interposed between bonding surfaces of round rods 1 and 2. An inert gas,
such as an Ar gas, an N.sub.2 gas, a mixture gas of Ar and N.sub.2, or the
like, is supplied from an inert gas supply source 5 into a housing 6 which
receives the round rods 1 and 2 to be bonded to each other, so that the
inside of the housing 6 is set in an atmosphere of inert gas. While
bonding portions of the round rods 1 and 2 are pressed by means of a
pressing device 4, and while bonding end portions of the round rods 1 and
2 are heated in the atmosphere of inert gas by high frequency resistance
heating, the round rods 1 and 2 are diffused-bonded to each other. In the
drawing, the reference numeral 21 designates electrodes for high frequency
resistance heating; and 22, a high-frequency electric source device.
Incidentally, in FIG. 5, constituent parts corresponding to those in FIG.
1 are referenced correspondingly.
With respect to the size, quality, etc., the insertion material 3 in this
Embodiment 5 is made the same as the insertion material 3 in the
Embodiment 1. Further, also the surface roughness of each of the bonding
surfaces of the round rods 1 and 2 which is pressed by the pressing device
4 in a state in which the insertion material 3 is interposed between the
bonding surfaces of the round rods 1 and 2. The pressure and the frequency
of a current for pressing the round rods 1 and 2 are made to be the same
as those in the Embodiment 1. That is, the surface roughness is not larger
than R.sub.max =50 .mu.m; the pressure, in a range of from 3 MPa to 9 MPa;
and the frequency of a current, not higher than 100 kHz, preferably in a
range of from 3 kHz to 30 kHz. Incidentally, the insertion material 3 may
be shaped like a ring in the same manner as in the Embodiment 1.
As described above, in this Embodiment 5, the disk-like or ring-like
insertion material 3 having a diameter slightly smaller than that of the
round rods 1 and 2 is used to perform diffusion bonding. Accordingly,
after bonding, the insertion material 3 is never excessively extruded to
the surfaces of the bonding portions. Accordingly, no finishing is
required on the bonding end portions after diffusion bonding. Accordingly,
the productivity and workability in diffusion bonding are improved
greatly.
Embodiment 6
In Embodiment 6 of the metal material bonding method according to the
present invention, round pipes 1 and 2 are bonded to each other by a
bonding apparatus A shown in FIG. 5 with use of an insertion material 3.
The size and shape of the insertion material 3 in this Embodiment 6 are
made to be the same as those of the insertion material 3 in the Embodiment
2.
Incidentally, with respect to other structures and operation/effect, the
Embodiment 6 is made the same as the Embodiment 5.
Embodiment 7
FIG. 6 is a schematic view showing a main part of a bonding apparatus used
in Embodiment 7 of the metal material bonding method according to the
present invention. In this bonding apparatus A, an insertion material 3 is
interposed between bonding surfaces of round rods 1 and 2. Air in a
housing 6 which receives the round rods 1 and 2 to be bonded to each other
is discharged by a vacuum pump 31 so that the inside of the housing 6 is
evacuated to a near vacuum in which the pressure of the inside of the
housing 6 is not higher than 5.times.10.sup.-2 mmHg. While the bonding
portions are pressed by a pressing device 4 and while the bonding end
portions are heated in the near vacuum by current conduction heating, the
round rods 1 and 2 are diffusion-bonded to each other. Incidentally, in
FIG. 6, the constituent parts corresponding to those in FIGS. 1 and 5 are
referenced correspondingly.
With respect to the size, quality, etc., the insertion material 3 in this
Embodiment 7 is made the same as the insertion material 3 in the
Embodiment 1. Further, also the surface roughness of each of the bonding
surfaces of the round rods 1 and 2 which is pressed by the pressing device
4 in a state in which the insertion material 3 is interposed between the
bonding surfaces of the round rods 1 and 2. The pressure and the frequency
of a current for pressing the round rods 1 and 2 are made to be the same
as those in the Embodiment 1. That is, the surface roughness is not larger
than R.sub.max =50 .mu.m; the pressure, in a range of from 3 MPa to 9 MPa;
and the frequency of a current, not higher than 100 kHz, preferably in a
range of from 3 kHz to 30 kHz. Incidentally, the insertion material 3 may
be shaped like a ring in the same manner as in the Embodiment 1.
As described above, in this Embodiment 7, the disk-like or ring-like
insertion material 3 having a diameter slightly smaller than that of the
round rods 1 and 2 is used to perform diffusion bonding. Accordingly,
after bonding, the insertion material 3 is never excessively extruded to
the surfaces of the bonding portions. Accordingly, no finishing is
required on the bonding end portions after diffusion bonding. Accordingly,
the productivity and workability in diffusion bonding are improved
greatly.
Embodiment 8
In Embodiment 8 of the metal material bonding method according to the
present invention, round pipes 1 and 2 are bonded to each other by a
bonding apparatus A shown in FIG. 6 with use of an insertion material 3.
The size and shape of the insertion material 3 in this Embodiment 8 are
made to be the same as those of the insertion material 3 in the Embodiment
2.
Incidentally, with respect to other structures and operation/effect, the
Embodiment 8 is made the same as the Embodiment 7.
Although the aforementioned Embodiments have shown the case where each of
the metal materials to be bonded is shaped like a round rod or a round
pipe, the shape of each of the metal materials to be bonded is not limited
to such a round shape. But any shape other than such a round rod (pipe)
may be used. For example, the metal materials may be shaped like
rectangular rods or rectangular pipes. Although the Embodiments have been
described above about the case of bonding in a horizontal posture by way
of example, the posture is not limited to such a case but any posture, for
example, an oblique posture may be used. Further, although the Embodiments
have shown a structure in which a pressing force is given to bonding
surfaces by pressing respective rear ends of two materials to be bonded to
each other, the present invention is not limited to such a structure, but
a pressing force may be given while at least one of the two materials to
be bonded is being grasped.
EXAMPLES
The present invention will be described below more specifically while
comparing various examples of this invention with comparative examples.
After stainless steel round rods and round pipes (SUS304) and carbon steel
rectangular pipes (SS400) were bonded under various conditions
respectively, a tensile test and a fatigue test were conducted. The
conditions and results of the tests at that time are as follows. Here, the
melting point of SUS304 is 1480.degree. C. and the melting point of SS400
is 1495.degree. C.
Examples 1 to 4 and Comparative Examples 1 to 3
Stainless steel round rods (SUS304: 50 mm outer diameter) shown in Table 1
were bonded to each other with use of an insertion material shown in Table
1 under a condition shown in Table 2. Then, the bonded stainless steel
round rods were subjected to a tensile test and a fatigue test. Results of
the test are as shown in Table 3.
It is apparent from the results shown in Table 3 that it is desirable to
select the ratio of the area of the insertion material to the area of each
bonding surface to be in a range of from 50% to 99%, preferably in a range
of from 51% to 98%.
Incidentally, in Table 2, the "distance" and "ratio" about the "outer edge"
mean the shortest distance from the outer edge of the insertion material
to the outer edge of each bonding surface, and the ratio of the distance
to the thickness of the insertion material, respectively. The "distance"
and "ratio" about the "inner edge" mean the largest distance from the
inner edge of the insertion material to the inner edge of each bonding
surface, and the ratio of the distance to the thickness of the insertion
material, respectively.
Further, the fatigue test was carried out by tensile compression under the
condition in which the number (Nf) of repetitions was 2.times.10.sup.6 and
the rate of repetition was 3 Hz.
TABLE 1
__________________________________________________________________________
Comp.
Comp.
Classification Ex. 1
Ex. 2
Example 1
Example 2
__________________________________________________________________________
Material
Quality SUS304
SUS304
SUS304
SUS304
to be bonded
Shape Round
Round
Round
Round
Rod Rod Rod Rod
Outer Diameter (mm)
.phi.50
.phi.50
.phi.50
.phi.50
Inner Diameter (mm)
-- -- -- --
Insertion
Shape Outer Diameter (mm)
.phi.50
.phi.50
.phi.49.4
.phi.44.0
Material Inner Diameter (mm)
-- -- -- --
Thickness (.mu.m)
30 30 30 30
Composition
Ni Bal.
Bal.
Bal. Bal.
(mass %)
Si -- -- -- --
Cr 15.0
15.0
15.0 15.0
Fe -- -- -- --
B 4.0 4.0 4.0 4.0
C -- -- -- --
__________________________________________________________________________
Comp.
Classification Example 3
Example 4
Ex. 3
__________________________________________________________________________
Material
Quality SUS304
SUS304
SUS304
to be bonded
Shape Round
Round Round
Rod Rod Rod
Outer Diameter (mm)
.phi.50
.phi.50
.phi.50
Inner Diameter (mm)
-- -- --
Insertion
Shape Outer Diameter (mm)
.phi.38.0
.phi.40
.phi.35
Material Inner Diameter (mm)
-- .phi.18
--
Thickness (.mu.m)
30 30 30
Composition
Ni Bal. Bal. Bal.
(mass %)
Si -- -- --
Cr 15.0 15.0 15.0
Fe -- -- --
B 4.0 4.0 4.0
C -- -- --
__________________________________________________________________________
TABLE 2
______________________________________
Comp. Comp. Exam- Exam-
Classification
Ex. 1 Ex. 2 ple 1 ple 2
______________________________________
Position with respect
to Bonding Surface
Outer Edge
Distance (mm) 0.0 0.0 0.3 3.0
Ratio (%) 0 0 10 100
Inner Edge
Distance (mm) -- -- -- --
Ratio (%) -- -- -- --
Area Ratio (%)
100 100 98 77
Bonding Condition
Bonding Surface
30 30 30 30
Roughness
(Rmax, .mu.m)
Heating
Method Induc- Induc- Induc- Induc-
tion tion tion tion
Heat Heat Heat Heat
Frequency 3 3 3 3
(kHz)
Bonding 1250 1250 1250 1250
Temperature (.degree. C.)
Holding Time (s)
60 60 60 60
Pressure (MPa)
4 4 4 4
Bonding Ar Ar Ar Ar
Atmosphere
______________________________________
Exam- Exam- Comp.
Classification ple 3 ple 4 Ex. 3
______________________________________
Position with respect
to Bonding Surface
Outer Edge
Distance (mm) 6.0 5.0 7.5
Ratio (%) 200 167 250
Inner Edge
Distance (mm) -- -- --
Ratio (%) -- -- --
Area Ratio (%) 58 51 49
Bonding Condition
Bonding Surface
30 30 30
Roughness
(Rmax, .mu.m)
Heating
Method Induc- Induc- Induc-
tion tion tion
Heat Heat Heat
Frequency 3 3 3
(kHz)
Bonding 1250 1250 1250
Temperature (.degree. C.)
Holding Time (s)
60 60 60
Pressure (MPa) 4 4 4
Bonding Ar Ar Ar
Atmosphere
______________________________________
TABLE 3
______________________________________
Comp. Comp.
Classification
Ex. 1 Ex. 2 Example 1
Example 2
______________________________________
Tensile
Tensile 640 644 642 641
Test Strength
(MPa)
Rupture Base Base Base Base
Position Material Material
Material
Material
Fatigue
Fatigue 160 230 230 230
Test Limit (MPa)
Rupture Bonding No Rupture
No No
Position Interface Rupture
Rupture
Evaluation C B A A
Remarks Bonding
portion was
treated to be
smoothened
______________________________________
Comp.
Classification Example 3
Example 4 Ex. 3
______________________________________
Tensile Test
Tensile Strength
641 642 587
(MPa)
Rupture Position
Base Base Base
Material Material
Material
Fatigue Test
Fatigue Limit (MPa)
230 230 150
Rupture Position
No No Rupture
Bonding
Rupture Interface
Evaluation A A C
Remarks Ring-like
insertion
material was
used.
______________________________________
Example 5 and Comparative Example 4
Stainless steel round rods (SUS304: 125 mm outer diameter) shown in Table 4
were bonded to each other with use of an insertion material shown in Table
4 under a condition shown in Table 5. Then, the bonded stainless steel
round rods were subjected to a tensile test and a fatigue test. Results of
the test are as shown in Table 6.
It is apparent from results shown in Table 6 that it is necessary to make
the distance about the outer edge be at least ten times as large as the
thickness of the insertion material.
Incidentally, in Table 5, the "distance" and "ratio" about the "outer edge"
mean the shortest distance from the outer edge of the insertion material
to the outer edge of each bonding surface, and the ratio of the distance
to the thickness of the insertion material, respectively. The "distance"
and "ratio" about the "inner edge" mean the largest distance from the
inner edge of the insertion material to the inner edge of each bonding
surface, and the ratio of the distance to the thickness of the insertion
material, respectively.
Further, the fatigue test was carried out by tensile compression under the
condition in which the number (Nf) of repetitions was 2.times.10.sup.6 and
the rate of repetition was 3 Hz.
TABLE 4
______________________________________
Comp.
Classification Example 5
Ex. 4
______________________________________
Material
Quality SUS304 SUS304
to be bonded
Shape Round Round
Rod Rod
Outer Diameter (mm) .phi.125 .phi.125
Inner Diameter (mm) -- --
Insertion
Shape Outer Diameter (mm)
.phi.124.4
.phi.125
Material Inner Diameter (mm)
-- .phi.12.5
Thickness (.mu.m)
30 30
Composition
Ni Bal. Bal.
(mass %) Si -- --
Cr 15.0 15.0
Fe -- --
B 4.0 4.0
C -- --
______________________________________
TABLE 5
______________________________________
Comp.
Classification Example 5
Ex. 4
______________________________________
Position with
Outer Distance (mm)
0.3 0.0
respect to
Edge Ratio (%) 10 0
Bonding Surface
Inner Distance (mm)
-- --
Edge Ratio (%) -- --
Area Ratio (%) 99 99
Bonding Bonding Surface Roughness
30 30
Condition (Rmax, .mu.m)
Heating
Method Induction
Induction
Heat Heat
Frequency (kHz)
3 3
Bonding Temperature (.degree. C.)
1250 1250
Holding Time (s)
180 180
Pressure (MPa) 4 4
Bonding Atmosphere
Ar Ar
______________________________________
TABLE 6
______________________________________
Classification Example 5 Comp. Ex. 4
______________________________________
Tensile Test
Tensile Strength
643 642
(MPa)
Rupture Position
Base Base Material
Material
Fatigue Test
Fatigue Limit (MPa)
230 200
Rupture Position
No Rupture
Bonding Interface
Evaluation A B
Remarks Rupture in bonding
interface with a large
fatigue limit.
______________________________________
Example 6 and 7 and Comparative Examples 5 and 6
Stainless steel round rods (SUS304: 125 mm outer diameter) shown in Table 7
were bonded to each other with use of an insertion material shown in the
same Table 7 under a condition shown in Table 8. Then, the bonded
stainless steel round rods were subjected to a tensile test and a fatigue
test. Results of the test are as shown in Table 9.
It is apparent from results shown in Table 9 that it is desirable to select
the boron content in the insertion material to be in a range of from 2
mass % to 5 mass %.
Incidentally, in Table 8, the "distance" and "ratio" about the "outer edge"
mean the shortest distance from the outer edge of the insertion material
to the outer edge of each bonding surface, and the ratio of the distance
to the thickness of the insertion material, respectively. The "distance"
and "ratio" about the "inner edge" mean the largest distance from the
inner edge of the insertion material to the inner edge of each bonding
surface, and the ratio of the distance to the thickness of the insertion
material, respectively.
Further, the fatigue test was carried out by tensile compression under the
condition in which the number (Nf) of repetitions was 2.times.10.sup.6 and
the rate of repetition was 3 Hz.
TABLE 7
______________________________________
Comp. Exam- Exam- Comp.
Classification
Ex. 5 ple 6 ple 7 Ex. 6
______________________________________
Material to be bonded
Quality SUS304 SUS304 SUS304 SUS304
Shape Round Round Round Round
Rod Rod Rod Rod
Outer Diameter
.phi.125 .phi.125 .phi.125
.phi.125
(mm)
Inner Diameter
-- -- -- --
(mm)
Insertion Material
Shape
Outer Diameter
.phi.122 .phi.122 .phi.122
.phi.122
(mm)
Inner Diameter
-- -- -- --
(mm)
Thickness (.mu.m)
30 30 30 30
Composition
(mass %)
Ni Bal. Bal. Bal. Bal.
Si -- -- -- --
Cr 15.0 15.0 15.0 15.0
Fe -- -- -- --
B 1.0 2.0 5.0 6.0
C -- -- -- --
______________________________________
TABLE 8
______________________________________
Comp. Exam- Exam- Comp.
Classification
Ex. 5 ple 6 ple 7 Ex. 6
______________________________________
Position with respect
to Bonding Surface
Outer Edge
Distance (mm) 1.5 1.5 1.5 1.5
Ratio (%) 50 50 50 50
Inner Edge
Distance (mm) -- -- -- --
Ratio (%) -- -- -- --
Area Ratio (%)
95 95 95 95
Bonding Condition
Bonding Surface
30 30 30 30
Roughness
(Rmax, .mu.m)
Heating
Method Induc- Induc- Induc- Induc-
tion tion tion tion
Heat Heat Heat Heat
Frequency 3 3 3 3
(kHz)
Bonding 1250 1250 1250 1250
Temperature (.degree. C.)
Holding Time (s)
180 180 180 180
Pressure (MPa)
4 4 4 4
Bonding Ar Ar Ar Ar
Atmosphere
______________________________________
TABLE 9
______________________________________
Comp. Exam- Exam- Comp.
Classification
Ex. 5 ple 6 ple 7 Ex. 6
______________________________________
Tensile Test
Tensile 549 641 644 588
Strength (MPa)
Rupture Bonding Base Base Bonding
Position Interface
Material Material
Interface
Fatigue Test
Fatigue Limit
130 230 230 200
(MPa)
Rupture Bonding No No Bonding
Position Interface
Rupture Rupture
Interface
Evaluation C A A C
Remarks
______________________________________
Example 8 and 9 and Comparative Examples 7 and 8
Stainless steel round rods (SUS304: 125 mm outer diameter) shown in Table
10 were bonded to each other with use of an insertion material shown in
the same Table 10 under a condition shown in Table 11. Then, the bonded
stainless steel round rods were subjected to a tensile test and a fatigue
test. Results of the test are as shown in Table 12.
It is apparent from results shown in Table 12 that it is desirable to
select the thickness of the insertion material to be in a range of from 20
.mu.m to 100 .mu.m.
Incidentally, in Table 11, the "distance" and "ratio" about the "outer
edge" mean the shortest distance from the outer edge of the insertion
material to the outer edge of each bonding surface, and the ratio of the
distance to the thickness of the insertion material, respectively. The
"distance" and "ratio" about the "inner edge" mean the largest distance
from the inner edge of the insertion material to the inner edge of each
bonding surface, and the ratio of the distance to the thickness of the
insertion material, respectively.
Further, the fatigue test was carried out by tensile compression under the
condition in which the number (Nf) of repetitions was 2.times.10.sup.6 and
the rate of repetition was 3 Hz.
TABLE 10
______________________________________
Comp. Exam- Exam- Comp.
Classification
Ex. 7 ple 8 ple 9 Ex. 8
______________________________________
Material to be
bonded
Quality SUS304 SUS304 SUS304 SUS304
Shape Round Round Round Round
Rod Rod Rod Rod
Outer Diameter
.phi.125 .phi.125 .phi.125
.phi.125
(mm)
Inner Diameter
-- -- -- --
(mm)
Insertion Material
Shape
Outer Diameter
.phi.122 .phi.122 .phi.122
.phi.122
(mm)
Inner Diameter
-- -- -- --
(mm)
Thickness (.mu.m)
10 20 100 120
Composition
(mass %)
Ni Bal. Bal. Bal. Bal.
Si -- -- -- --
Cr 15.0 15.0 15.0 15.0
Fe -- -- -- --
B 4.0 4.0 4.0 4.0
C -- -- -- --
______________________________________
TABLE 11
______________________________________
Comp. Exam- Exam- Comp.
Classification
Ex. 7 ple 8 ple 9 Ex. 8
______________________________________
Position with respect
to Bonding Surface
Outer Edge
Distance (mm) 1.5 1.5 1.5 1.5
Ratio (%) 50 50 50 50
Inner Edge
Distance (mm) -- -- -- --
Ratio (%) -- -- -- --
Area Ratio (%)
95 95 95 95
Bonding Condition
Bonding Surface
30 30 30 30
Roughness
(Rmax, .mu.m)
Heating
Method Induc- Induc- Induc- Induc-
tion tion tion tion
Heat Heat Heat Heat
Frequency 3 3 3 3
(kHz)
Bonding 1250 1250 1250 1250
Temperature (.degree. C.)
Holding Time (s)
180 180 180 180
Pressure (MPa)
4 4 4 4
Bonding Ar Ar Ar Ar
Atmosphere
______________________________________
TABLE 12
______________________________________
Comp. Comp.
Classification
Ex. 7 Example 8
Example 9
Ex. 8
______________________________________
Tensile
Tensile 555 642 641 608
Test Strength
(MPa)
Rupture Bonding Base Base Bonding
Position Interface
Material
Material
Interface
Fatigue
Fatigue 140 230 230 210
Test Limit (MPa)
Rupture Bonding No No Bonding
Position Interface
Rupture
Rupture
Interface
Evaluation C A A C
Remarks
______________________________________
Example 10 and 11 and Comparative Examples 9 and 10
Stainless steel pipes (SUS304: 165 mm outer diameter.times.145 inner
diameter) shown in Table 13 were bonded with use of an insert material
shown in the same Table 13 under the condition shown in Table 14. Then, a
tensile test and a fatigue test were conducted on the bonded stainless
steel pipes. The results are shown in Table 15.
It is apparent from the results shown in Table 15 that it is desirable to
select the ratio of the area of the insertion material to the area of each
bonding surface to be in a range of from 50% to 99%, preferably in a range
of from 51% to 98%.
Incidentally, in Table 14, the "distance" and "ratio" about the "outer
edge" mean the shortest distance from the outer edge of the insertion
material to the outer edge of each bonding surface, and the ratio of the
distance to the thickness of the insertion material, respectively. The
"distance" and "ratio" about the "inner edge" mean the largest distance
from the inner edge of the insertion material to the inner edge of each
bonding surface, and the ratio of the distance to the thickness of the
insertion material, respectively.
Further, the fatigue test was carried out by tensile compression under the
condition in which the number (Nf) of repetitions was 2.times.10.sup.6 and
the rate of repetition was 3 Hz.
TABLE 13
______________________________________
Comp. Exam- Exam- Comp.
Classification
Ex. 9 ple 10 ple 11 Ex. 10
______________________________________
Material to be
bonded
Quality SUS304 SUS304 SUS304 SUS304
Shape Pipe Pipe Pipe Pipe
Outer Diameter
.phi.165 .phi.165 .phi.165
.phi.165
(mm)
Inner Diameter
.phi.145 .phi.145 .phi.145
.phi.145
(mm)
Insertion Material
Shape
Outer Diameter
.phi.165 .phi.164.2
.phi.164.2
.phi.155
(mm)
Inner Diameter
.phi.145 .phi.145 .phi.154.4
.phi.145
(mm)
Thickness 40 40 40 40
(.mu.m)
Composition
(mass %)
Ni Bal. Bal. Bal. Bal.
Si 4.0 4.0 4.0 4.0
Cr 8.0 8.0 8.0 8.0
Fe 3.0 3.0 3.0 3.0
B 4.0 4.0 4.0 4.0
C -- -- -- --
______________________________________
TABLE 14
______________________________________
Comp. Exam- Exam- Comp.
Classification
Ex. 9 ple 10 ple 11 Ex. 10
______________________________________
Position with respect
to Bonding Surface
Outer Edge
Distance (mm) 0.0 0.4 0.4 5.0
Ratio (%) 0 10 10 125
Inner Edge
Distance (mm) 0.0 0.0 0.7 0.0
Ratio (%) 0 0 18 0
Area Ratio (%)
100 96 50 48
Bonding Condition
Bonding Surface
30 30 30 30
Roughness
(Rmax, .mu.m)
Heating
Method Induc- Induc- Induc- Induc-
tion tion tion tion
Heat Heat Heat Heat
Frequency 3 3 3 3
(kHz)
Bonding 1250 1250 1250 1250
Temperature (.degree. C.)
Holding Time (s)
120 120 120 120
Pressure (MPa)
4 4 4 4
Bonding Ar Ar Ar Ar
Atmosphere
______________________________________
TABLE 15
______________________________________
Comp. Example Example
Comp.
Classification
Ex. 9 10 11 Ex. 10
______________________________________
Tensile
Tensile 648 643 640 639
Test Strength
(MPa)
Rupture Base Base Base Base
Position Material Material
Material
Material
Fatigue
Fatigue 210 230 230 220
Test Limit (MPa)
Rupture Bonding No No Bonding
Position Interface
Rupture
Rupture
Interface
Evaluation B A A B
Remarks Rupture in
bonding
interface
with a large
fatigue limit.
______________________________________
Example 12 and 13 and Comparative Examples 11 and 12
Stainless steel pipes (SUS304: 165 mm outer diameter.times.145 inner
diameter) shown in Table 16 were bonded with use of an insert material
shown in the same Table 16 under the condition shown in Table 17. Then, a
tensile test and a fatigue test were conducted on the bonded stainless
steel pipes. The results are shown in Table 18.
It is apparent from results shown in Table 18 that it is desirable to
select the thickness of the insertion material to be in a range of from 20
.mu.m to 100 .mu.m.
Incidentally, in Table 17, the "distance" and "ratio" about the "outer
edge" mean the shortest distance from the outer edge of the insertion
material to the outer edge of each bonding surface, and the ratio of the
distance to the thickness of the insertion material, respectively. The
"distance" and "ratio" about the "inner edge" mean the largest distance
from the inner edge of the insertion material to the inner edge of each
bonding surface, and the ratio of the distance to the thickness of the
insertion material, respectively.
Further, the fatigue test was carried out by tensile compression under the
condition in which the number (Nf) of repetitions was 2.times.10.sup.6 and
the rate of repetition was 3 Hz.
TABLE 16
______________________________________
Exam- Exam- Comp. Comp.
Classification
ple 12 ple 13 Ex. 11 Ex. 12
______________________________________
Material to be
bonded
Quality SUS304 SUS304 SUS304 SUS304
Shape Pipe Pipe Pipe Pipe
Outer Diamter .phi.165 .phi.165 .phi.165
.phi.165
(mm)
Inner Diameter
.phi.145 .phi.145 .phi.145
.phi.145
(mm)
Insertion Material
Shape
Outer Diameter
.phi.160 .phi.160 .phi.160
.phi.164.2
(mm)
Inner Diameter
.phi.146 .phi.146 .phi.146
.phi.154.4
(mm)
Thickness (.mu.m)
Composition
(mass %)
Ni Bal. Bal. Bal. Bal.
Si 4.0 4.0 4.0 4.0
Cr 8.0 8.0 8.0 8.0
Fe 3.0 3.0 3.0 3.0
B 2.0 5.0 4.0 4.0
C -- -- -- --
______________________________________
TABLE 17
______________________________________
Exam- Exam- Comp. Comp.
Classification
ple 12 ple 13 Ex. 11 Ex. 12
______________________________________
Position with respect
to Bonding Surface
Outer Edge
Distance (mm) 2.5 2.5 2.5 2.5
Ratio (%) 63 63 63 63
Inner Edge
Distance (mm) 0.5 0.5 0.5 0.5
Ratio (%) 13 13 13 13
Area Ratio (%)
69 69 69 69
Bonding Condition
Bonding Surface
30 30 30 30
Roughness
(Rmax, .mu.m)
Heating
Method Induc- Induc- Induc- Induc-
tion tion tion tion
Heat Heat Heat Heat
Frequency 3 3 3 3
(kHz)
Bonding 1250 1250 1250 1250
Temperature (.degree. C.)
Holding Time (s)
120 120 120 120
Pressure (MPa)
4 4 4 4
Bonding Ar Ar Ar Ar
Atmosphere
______________________________________
TABLE 18
______________________________________
Example Example Comp. Comp.
Classification
12 13 Ex. 11 Ex. 12
______________________________________
Tensile
Tensile 634 646 567 597
Test Strength
(MPa)
Rupture Base Base Bonding
Bonding
Position Material Material
Interface
Interface
Fatigue
Fatigue 230 230 160 180
Test Limit (MPa)
Rupture No No Bonding
Bonding
Position Rupture Rupture
Interface
Interface
Evaluation A A C C
Remarks
______________________________________
Example 14 and Comparative Example 13
Carbon steel rectangular pipes (SS400: 100 mm square.times.80 mm square)
shown in Table 19 were bonded to each other with use of an insertion
material shown in the same Table 19 under a condition shown in Table 20.
Then, the bonded carbon steel rectangular pipes were subjected to a
tensile test and a fatigue test. Results of the test are as shown in Table
21.
It is apparent from results shown in Table 21 that it is necessary to
select the surface roughness R.sub.max of each bonding surface to be not
larger than 50 .mu.m.
Incidentally, in Table 20, the "distance" and "ratio" about the "outer
edge" mean the shortest distance from the outer edge of the insertion
material to the outer edge of each bonding surface, and the ratio of the
distance to the thickness of the insertion material, respectively. The
"distance" and "ratio" about the "inner edge" mean the largest distance
from the inner edge of the insertion material to the inner edge of each
bonding surface, and the ratio of the distance to the thickness of the
insertion material, respectively.
Further, the fatigue test was carried out by tensile compression under the
condition in which the number (Nf) of repetitions was 2.times.10.sup.6 and
the rate of repetition was 3 Hz.
TABLE 19
______________________________________
Comp.
Classification Ex. 13 Example 14
______________________________________
Material
Quality SS400 SS400
to be bonded
Shape Rectangular
Rectangular
Pipe Pipe
Outer Size (mm) .quadrature.100
.quadrature.100
Inner Size (mm) .quadrature.80
.quadrature.80
Insertion
Shape Outer Size .quadrature.98.8
.quadrature.98.8
Material (mm)
Inner Size .quadrature.80
.quadrature.80
(mm)
Thickness (.mu.m)
30 30
Composition
Ni -- --
(mass %) Si 3.0 3.0
Cr -- --
Fe Bal. Bal.
B 3.0 3.0
C 1.5 1.5
______________________________________
TABLE 20
______________________________________
Comp.
Classification Ex. 13 Example 14
______________________________________
Position with
Outer Distance (mm)
0.6 0.6
respect to
Edge Ratio (%) 20 20
Bonding Surface
Inner Distance (mm)
0.0 0.0
Edge Ratio (%) 0 0
Area Ratio (%) 66 66
Bonding Bonding Surface Rough-
60 50
Condition ness (Rmax, .mu.m)
Heating
Method Induction
Induction
Heat Heat
Frequency (kHz)
3 3
Bonding Temperature
1250 1250
(.degree. C.)
Holding Time (s)
60 60
Pressure (MPa)
4 4
Bonding Atmosphere
Ar Ar
______________________________________
TABLE 21
______________________________________
Classification Comp. Ex. 13
Example 14
______________________________________
Tensile Test
Tensile Strength
430 450
(MPa)
Rupture Position
Bonding Interface
Base Material
Fatigue Test
Fatigue Limit (MPa)
210 270
Rupture Position
Bonding Interface
No Rupture
Evaluation C A
Remarks
______________________________________
Example 15 and 16 and Comparative Examples 14 and 15
Carbon steel rectangular pipes (SS400: 100 mm square.times.80 mm square)
shown in Table 22 were bonded to each other with use of an insertion
material shown in the same Table 22 under a condition shown in Table 23.
Then, the bonded carbon steel rectangular pipes were subjected to a
tensile test and a fatigue test. Results of the test are as shown in Table
24.
It is apparent from results shown in Table 24 that it is desirable to
select the pressure to be applied to be in a range of from 3 MPa to 9 MPa.
Incidentally, in Table 23, the "distance" and "ratio" about the "outer
edge" mean the shortest distance from the outer edge of the insertion
material to the outer edge of each bonding surface, and the ratio of the
distance to the thickness of the insertion material, respectively. The
"distance" and "ratio" about the "inner edge" mean the largest distance
from the inner edge of the insertion material to the inner edge of each
bonding surface, and the ratio of the distance to the thickness of the
insertion material, respectively.
Further, the fatigue test was carried out by tensile compression under the
condition in which the number (Nf) of repetitions was 2.times.10.sup.6 and
the rate of repetition was 3 Hz.
TABLE 22
______________________________________
Comp. Exam- Exam- Comp.
Classification
Ex. 14 ple 15 ple 16 Ex. 15
______________________________________
Material to be bonded
Quality SS400 SS400 SS400 SS400
Shape Rectan- Rectan- Rectan-
Rectan-
gular gular gular gular
Pipe Pipe Pipe Pipe
Outer Size .quadrature.100
.quadrature.100
.quadrature.100
.quadrature.100
(mm)
Inner Size .quadrature.80
.quadrature.80
.quadrature.80
.quadrature.80
(mm)
Insertion Material
Shape
Outer Size .quadrature.98.8
.quadrature.98.8
.quadrature.98.8
.quadrature.98.8
(mm)
Inner Size .quadrature.80
.quadrature.80
.quadrature.80
.quadrature.80
(mm)
Thickness 30 30 30 30
(.mu.m)
Composition
(mass %)
Ni -- -- -- --
Si 3.0 3.0 3.0 3.0
Cr -- -- -- --
Fe Bal. Bal. Bal. Bal.
B 3.0 3.0 3.0 3.0
C 1.5 1.5 1.5 1.5
______________________________________
TABLE 23
______________________________________
Comp. Exam- Exam- Comp.
Classification
Ex. 14 ple 15 ple 16 Ex. 15
______________________________________
Position with respect
to Bonding Surface
Outer Edge
Distance (mm) 0.6 0.6 0.6 0.6
Ratio (%) 20 20 20 20
Inner Edge
Distance (mm) 0.0 0.0 0.0 0.0
Ratio (%) 0 0 0 0
Area Ratio (%)
66 66 66 66
Bonding Condition
Bonding Surface
30 30 30 30
Roughness
(Rmax, .mu.m)
Heating
Method Induc- Induc- Induc- Induc-
tion tion tion tion
Heat Heat Heat Heat
Frequency 3 3 3 3
(kHz)
Bonding 1250 1250 1250 1250
Temperature (.degree. C.)
Holding Time (s)
60 60 60 60
Pressure (MPa)
2 3 9 10
Bonding N.sub.2 N.sub.2 N.sub.2
N.sub.2
Atmosphere
______________________________________
TABLE 24
______________________________________
Comp. Exam- Exam- Comp.
Classification
Ex. 14 ple 15 ple 16 Ex. 15
______________________________________
Tensile Test
Tensile 388 447 445 420
Strength (MPa)
Rupture Bonding Base Base Base
Position Inter- Ma- Ma- Ma-
face terial terial terial
Fatigue Test
Fatigue Limit
170 270 270 200
(MPa)
Rupture Bonding No No Bonding
Position Inter- Rup- Rup- Inter-
face ture ture face
Evaluation x .smallcircle.
.smallcircle.
.DELTA.
Remarks Ex-
cessive
Defor-
mation
in
Bonding
Portion.
______________________________________
Examples 17 to 19 and Comparative Examples 16 to 18
Carbon steel rectangular pipes (SS400: 100 mm square.times.80 mm square)
shown in Table 25 were bonded to each other with use of an insertion
material shown in the same Table 25 under a condition shown in Table 26.
Then, the bonded carbon steel rectangular pipes were subjected to a
tensile test and a fatigue test. Results of the test are as shown in Table
27.
It is apparent from results shown in Table 27 that it is preferable to
carry out bonding in a vacuum or in a nitrogen gas atmosphere under the
condition in which the frequency of a current is in a range of from 3 kHz
to 100 kHz.
Incidentally, in Table 26, the "distance" and "ratio" about the "outer
edge" mean the shortest distance from the outer edge of the insertion
material to the outer edge of each bonding surface, and the ratio of the
distance to the thickness of the insertion material, respectively. The
"distance" and "ratio" about the "inner edge" mean the largest distance
from the inner edge of the insertion material to the inner edge of each
bonding surface, and the ratio of the distance to the thickness of the
insertion material, respectively.
Further, the fatigue test was carried out by tensile compression under the
condition in which the number (Nf) of repetitions was 2.times.10.sup.6 and
the rate of repetition was 3 Hz.
TABLE 25
______________________________________
Exam- Comp. Exam- Comp. Exam- Comp.
Classification
ple 17 Ex. 16 ple 18
Ex. 17
ple 19
Ex. 18
______________________________________
Material to
be bonded
Quality SS400 SS400 SS400 SS400 SS400 SS400
Shape Rectan- Rectan- Rectan-
Rectan-
Rectan-
Rectan-
gular gular gular gular gular gular
Pipe Pipe Pipe Pipe Pipe Pipe
Outer Size
.quadrature.100
.quadrature.100
.quadrature.100
.quadrature.100
.quadrature.100
.quadrature.100
(mm)
Inner Size
.quadrature.80
.quadrature.80
.quadrature.80
.quadrature.80
.quadrature.80
.quadrature.80
(mm)
Insertion
Material
Shape
Outer Size
.quadrature.98.8
.quadrature.98.8
.quadrature.98.8
.quadrature.98.8
.quadrature.98.8
.quadrature.98.8
(mm)
Inner Size
.quadrature.80
.quadrature.80
.quadrature.80
.quadrature.80
.quadrature.80
.quadrature.80
(mm)
Thickness
30 30 30 30 30 30
(.mu.m)
Composition
(mass %)
Ni -- -- -- -- -- --
Si 3.0 3.0 3.0 3.0 3.0 3.0
Cr -- -- -- -- -- --
Fe Bal. Bal. Bal. Bal. Bal. Bal.
B 3.0 3.0 3.0 3.0 3.0 3.0
C 1.5 1.5 1.5 1.5 1.5 1.5
______________________________________
TABLE 26
______________________________________
Exam- Comp. Exam- Comp. Exam- Comp.
Classification
ple 17 Ex. 16 ple 18
Ex. 17
ple 19
Ex. 18
______________________________________
Position with
respect to
Bonding
Surface
Outer Edge
Distance 0.6 0.6 0.6 0.6 0.6 0.6
(mm)
Ratio (%)
20 20 20 20 20 20
Inner Edge
Distance 0.0 0.0 0.0 0.0 0.0 0.0
(mm)
Ratio (%)
0 0 0 0 0 0
Area Ratio
66 66 66 66 66 66
(%)
Bonding
Condition
Bonding 30 30 30 30 30 30
Surface
Roughness
(Rmax, .mu.m)
Heating
Method Induc- Induc- Induc-
Induc-
Induc-
Induc-
tion tion tion tion tion tion
Heat Heat Heat Heat Heat Heat
Frequency
3 3 100 200 100 200
(kHz)
Bonding 1250 1250 1250 1250 1250 1250
Temperature
(.degree. C.)
Holding 60 60 60 60 60 60
Time (s)
Pressure 4 4 4 4 4 4
(MPa)
Bonding Vacuum Air N.sub.2
N.sub.2
Vacuum
Vacuum
Atmosphere
______________________________________
TABLE 27
______________________________________
Classi-
Exam- Comp. Exam- Comp. Exam- Comp.
fication
ple 17 Ex. 16 ple 18
Ex. 17 ple 19
Ex. 18
______________________________________
Tensile
Test
Tensile
444 321 449 399 443 401
Strength
(MPa)
Rupture
Base Bonding Base Bonding
Base Bonding
Position
Ma- Inter- Ma- Inter- Ma- Inter-
terial face terial
face terial
face
Fatigue
Test
Fatigue
270 110 270 180 270 190
Limit
(MPa)
Rupture
No Bonding No Bonding
No Bonding
Position
Rup- Inter- Rup- Inter- Rup- Inter-
ture face ture face ture face
Evalua-
A C A C A C
tion
Re-
marks
______________________________________
As described above in detail, according to the present invention, the
insertion material is prevented from being partly excessively extruded to
bonding end portions and solidified thereat, at the time of bonding.
Accordingly, there arises an excellent effect that both the workability
and productivity in metal material bonding can be improved. Further,
because the insertion material is prevented from being partly excessively
extruded to bonding end portions and solidified thereat, at the time of
bonding, there arises an excellent effect that the fatigue strength
against the metal materials bonded to each other is never lowered.
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